7. Much of China’s History Has Revolved Around Flood Control
An enormous quantity of silt – about 1.5 billion tons each year – is carried by the Yellow River. Throughout most of China’s history, the river was not dredged. The result was a steady accumulation of silt at the bottom, causing the river bed to steadily rise. A rising river bed is bad for those who live and farm along its banks. The shallower the river gets, the wider it becomes, and that carries the threat of flood to adjacent lands. Much of China’s history has been about preventing that from happening, usually with massively labor intensive projects to line the Yellow River with protective dikes. As the river rose over the years, so did the dikes. This went on for thousands of years, until China ended up with a river that flows along at an elevated level, often higher than the adjacent land. So when dikes failed, the results were catastrophic.
